1. Field of the Invention
The present invention relates to a herbicide applying machine, and more particularly to such a machine which blows debris from the ground surface along a row of plants to be weeded or sterilized and immediately thereafter applies herbicide to said ground surface.
2. Description of the Prior Art
The prior art includes various approaches for controlling weeds in commercial agriculture. Mechanical weeding, as by special plows, present difficulties in avoiding damage to individual plants of the crop, especially when they are relatively closely planted in rows, and in any case results in uncovering buried weed seeds which then germinate.
The use of herbicides avoids these problems, but existing machines for applying herbicides are relatively ineffective when used with herbicides which are placed in or on the soil since the herbicide is absorbed by debris, such as dead leaves, which blows away or is otherwise removed taking the herbicide with it. This problem is particularly serious with row crops since debris tends to accumulate along the rows of trunks or stems where it is especially desired to apply the herbicide. If an air stream is used to carry the herbicide to the row, a method commonly used in the art, and the air stream is given sufficient velocity to remove the debris, the velocity must be higher than is required only for applying the herbicide resulting in overspray, or application of herbicides beyond the desired area, and waste of herbicide by its absorption by the debris or deposit thereon. Overspray is of particular importance in an era where the dangers to the environment from agricultural chemicals are of increasing concern and is, in any event, a further waste of herbicide.
The problems of applying herbicides are complicated by the desirability of having a machine which can apply herbicides to crops of greatly varying row widths with, in some cases, the need to avoid contact of the herbicide with plants growing between the rows. A particular complication arises from the common practice of mixing for simultaneous application herbicides which require soil contact with herbicides which require leaf contact so that the spray used for applying the herbicides must be directed for proper application to both leaves and soil without the waste and environmental dangers of overspraying.